1. Field of the Invention
The present invention generally relates to a method and a device for removing and conveying semiconductor chips and, more particularly, to a method and a device for removing and conveying semiconductor chips by removing a dicing tape from the semiconductor chips formed and diced on a wafer and conveying the semiconductor chips stripped of the dicing tape.
2. Description of the Related Art
Conventionally, a dicing tape is applied to a plurality of semiconductor chips formed on a wafer. Dicing then divides the semiconductor chips into separate semiconductor chips. The dicing tape is removed from the separate semiconductor chips. The separate semiconductor chips are then conveyed to predetermined locations, being held by such a method as a vacuum pick-up method.
As a dicing tape, an adhesive ultravioletcure pressure-sensitive tape (referred to as UV tape) is generally used. The UV tape is cured by ultraviolet ray projection after dicing. This reduces the adhesion force of the UV tape to the semiconductor chips and facilitates the removal of the semiconductor chips from the UV tape.
Generally, semiconductor chips are removed from a dicing tape by a needle push-up method, wherein pressing a needle against the semiconductor chips from the backside of the dicing tape and pushing up the semiconductor chips removes the semiconductor chips from the dicing tape. The needle has a pointed end and breaks through the dicing tape to reach and push up the semiconductor chips. The semiconductor chips removed from the dicing tape are held by collets.
Recently, the size of semiconductor chips has been increased, while the thickness thereof has been decreased. These semiconductor chips are likely to be damaged by the above-mentioned needle push-up method. That is, because the needle concentrates stress on a point where it contacts, pushing up by the needle may break or chip the semiconductor chips. In some cases, the sharp pointed end of the needle may leave a scratch on the semiconductor chips, which scratch may later cause the semiconductor chips to break.
It is a general object of the present invention to provide an improved and useful method for removing and conveying semiconductor chips in which method the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a method and a device for removing and conveying semiconductor chips which method and device can remove the semiconductor chips from a dicing tape by a removing method and immediately pick up and convey the semiconductor chips.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a method of removing and conveying semiconductor chips, the method comprising the steps of:
dicing a wafer while keeping intact a dicing tape applied to the wafer, the wafer having a plurality of semiconductor chips formed thereon;
fixing by suction a surface of each of the semiconductor chips, the surface being opposite to another surface to which the dicing tape is applied;
removing the dicing tape from the semiconductor chips; and
picking up and conveying the semiconductor chips while unfixing the semiconductor chips by ceasing suction.
According to the present invention, the dicing tape is removed from the semiconductor chips while the surface opposite to where the dicing tape is applied is fixed by suction. In the removing step herein, the needle push-up method is not used so as to prevent the needle from damaging the semiconductor chips. Also, in this manner, the dicing tape can be removed easily from thin-type semiconductor chips to which the needle push-up method is not applicable. Additionally, the semiconductor chips removed from the dicing tape can be immediately picked up by such a method as vacuum pick-up, then continually followed by the conveying step. Accordingly, the steps from dicing through removing the dicing tape to conveying can be performed continuously to simplify the semiconductor chip manufacturing steps.
Additionally, in the present invention, the step of picking up and conveying the semiconductor chips is performed after removing the dicing tape from all of the semiconductor chips.
According to the present invention, the semiconductor chips are picked up and conveyed after the removal of the dicing tape from all of the semiconductor chips. Here, the step of picking up and conveying is required to be performed only once, thus simplifying the step.
Additionally, in the present invention, the step of removing and the step of picking up and conveying are repeated for each row of the semiconductor chips, in a manner of removing the dicing tape from one row of the semiconductor chips, picking up and conveying the one row of the semiconductor chips and then removing the dicing tape from the next row of the semiconductor chips.
According to the present invention, the dicing tape is removed from one row at a time, and the one row is then picked up and conveyed. Therefore, the rest of the semiconductor chips yet to undergo the steps of removing, picking up and conveying remain attached to and protected by the dicing tape.
Additionally, in the present invention, the dicing tape is divided into strips along rows of the semiconductor chips in dicing the wafer; and
the step of removing and the step of picking up and conveying are performed individually for each of the semiconductor chips, in a manner of removing the dicing tape from one chip in one row of the semiconductor chips, immediately picking up and conveying the one semiconductor chip and then removing the dicing tape from another semiconductor chip.
According to the present invention, each of the semiconductor chips is individually removed from the dicing tape and conveyed. Therefore, the semiconductor chips remain attached to and protected by the dicing tape until the removing step.
Additionally, in order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a method of removing and conveying semiconductor chips, the method comprising the steps of:
dicing a wafer while keeping intact a dicing tape applied to the wafer, the wafer having a plurality of semiconductor chips formed thereon;
placing the semiconductor chips on a removing stage with the side to which the dicing tape is applied facing downward;
removing the dicing tape from the semiconductor chips by bending a margin of the dicing tape downward around an edge of the removing stage and moving the removing stage while pulling the margin of the dicing tape downward;
transferring the semiconductor chips removed from the dicing tape to a chip receptacle by arranging the chip receptacle close to the edge of the removing stage and moving the chip receptacle together with the removing stage; and
picking up and conveying the semiconductor chips transferred to the chip receptacle.
According to the present invention, since the semiconductor chips do not need to be fixed during the step of removing the dicing tape, a removing mechanism can be simplified. Additionally, in the removing step herein, the needle push-up method is not used so as to prevent the needle from damaging the semiconductor chips. Also, in this manner, the dicing tape can be removed easily from thin-type semiconductor chips to which the needle push-up method is not applicable. Additionally, the semiconductor chips removed from the dicing tape can be immediately picked up by such a method as vacuum pick-up, then continually followed by the conveying step. Accordingly, the steps from dicing through removing the dicing tape to conveying can be performed continuously to simplify the semiconductor chip manufacturing steps.
Additionally, in order to achieve the above-mentioned objects, there is provided according to still another aspect of the present invention a device for removing a dicing tape from a wafer and conveying a plurality of semiconductor chips formed on the wafer, the wafer being diced with the dicing tape kept intact, the device comprising:
a vacuum chuck unit which fixes by suction a surface of the semiconductor chips, the surface being opposite to another surface to which the dicing tape is applied;
a removing mechanism which removes the dicing tape from the semiconductor chips;
a first shutter provided on a fixing part of the vacuum chuck unit and movable in predetermined directions, which first shutter closes openings which, before the semiconductor chips are conveyed, fixes the semiconductor chips by suction;
a second shutter provided on the fixing part of the vacuum chuck unit and movable in directions perpendicular to the directions in which the first shutter is movable, which second shutter closes openings for fixing so as to unfix the semiconductor chips by ceasing suction; and
a pick up head which picks up and conveys the semiconductor chips unfixed by ceasing suction.
According to the present invention, the second shutter can individually unfix by ceasing suction the semiconductor chips removed from the dicing tape and targeted to be picked up. Thereby, the rest of the semiconductor chips yet to be picked up and conveyed can remain fixed by continued suction. Additionally, the first shutter closes the openings for fixing which, before the semiconductor chips were picked up and conveyed, had been fixing the semiconductor chips by suction. Thus, the rest of the semiconductor chips yet to be picked up and conveyed remain properly fixed, unaffected by the otherwise continued suction of the openings.
Additionally, in order to achieve the above-mentioned objects, there is further provided according to another aspect of the present invention a device for removing a dicing tape from a wafer and conveying a plurality of semiconductor chips formed on the wafer, the wafer being diced with the dicing tape kept intact, the device comprising:
a mobile chuck capable of moving in predetermined directions, which mobile chuck individually fixes by suction each chip in one row of the semiconductor chips from a surface opposite to another surface to which the dicing tape is applied and which mobile chuck is capable of unfixing any of the semiconductor chips by ceasing suction;
a removing mechanism which removes the dicing tape from the semiconductor chips fixed by suction by the mobile chuck; and
a pick up head which picks up and conveys the semiconductor chips unfixed by ceasing suction.
According to the present invention, the dicing tape can be removed from one row at a time, and the one row can then be picked up and conveyed. Therefore, the rest of the semiconductor chips yet to undergo the steps of removing, picking up and conveying remain attached to and protected by the dicing tape. Additionally, the mobile chuck individually fixes by suction another row of the semiconductor chips after one row is removed from the dicing tape. Herein, the mobile chuck can individually unfix each of the semiconductor chips. Accordingly, all or any number of the semiconductor chips in one row can be picked up at a time.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.